Urinary Neutrophil Gelatinase-Associated Lipocalin as a Biomarker for Renal Injury in Liver Transplant Recipients Using Calcineurin Inhibitors

Abstract Background Urinary neutrophil gelatinase-associated lipocalin (uNGAL) is an early biomarker of renal injury. We examined the feasibility of using uNGAL as an early predictor of renal impairment in patients under calcineurin inhibitors in liver transplant recipients. Methods From urine samples obtained from liver transplant recipients, the glomerular filtration rate (GFR) at the time of urine sampling was compared with that at 5 to 7 months later. Patients were divided into 3 groups according to initial GFR and then divided into 2 groups according to the uNGAL level of 25 ng/mL. Progression of renal injury (PRI) was defined as a decrease in the GFR of more than 5 mL/min/1.73 m 2 in the mild or moderate groups, or if a normal group patient shifted to the mild or moderate group. Results Fifty-one patients were enrolled. The mean uNGAL level was higher in the moderate group than in the normal and mild groups (18.38 ± 14.31 vs 7.74 ± 8.13; P P  = .03). uNGAL-high was a risk factor for 6-month PRI (odds ratio, 60.375; 95% confidence interval, 1.283–4088.25; P  = .037) and 1-year PRI (odds ratio, 21.311; % confidence interval, 0.947–479.578; P  = .054). Conclusions A uNGAL of >25 ng/mg can be a marker for moderate renal impairment (GFR of 30–59 mL/min/1.73 m 2 ) and a predictor of PRI at 6 months in patients using calcineurin inhibitors. Renal protection strategies should be considered in liver transplant recipients with a uNGAL of >25 ng/mg in spot urine sampling.